Microsoft Surface 3
Microsoft's Surface 3 is a legit iPad challenger. Microsoft

Less than a week until the launch of Windows 10, Microsoft started rolling out the Surface 3 LTE to its stores, partner retailers and authorized resellers, with the tablet going on sale late Friday.

AT&T will be the first carrier to sell the tablet through its stores, with T-Mobile offering the device from July 31 through its @Work channel. Microsoft is also offering AT&T and T-Mobile SIM cards at its stores for purchasing customers. The tablet comes in both 64GB and 128GB variants and is not locked to a carrier. A Microsoft source has told ZDNet the tablet will retail for around $100 more than its WiFi counterparts, putting it at $599 and $699 for the smaller and larger storage sizes.

"Surface 3 brings the best of Surface Pro 3 in a compact and affordable package, and the 4G LTE version will be a great fit for a lot of people who need to stay connected beyond the reach of Wi-Fi," said Brian Hall, general manager of Microsoft Surface on the team blog.

Following the launch, the company plans to bring the model to unspecificed additional markets. "I’m excited to see the availability of the Surface 3 (4G LTE) growing and will provide future updates as we have them," said Hall.

The tablet does not come with Windows 10, but Microsoft is offering free upgrades from the currently-shipping Windows 8.1 operating system on July 29. The release has been finalized, and computer makers are preparing to ship models with the new version pre-installed.

Windows 10 brings a variety of features that will benefit the Surface, such as Continuum, which adapts the interface depending on whether the user is on a touchscreen or a keyboard and mouse. The Type Cover, which adds a keyboard and touchpad for $130.